Anchor Shear Capacity in Double Wythe Brick
Anchor Shear Capacity in Double Wythe Brick
(OP)
Does anyone know where could I find the allowable shear for anchor bolts embeded in the collared joint at double wythe bricks wall?
ACI 530 Commentary Section 2.1.5.2 states that the shear bond strength of collar joints with mortar could vary from 5 psi to as high as 100 psi. I was trying to find some publications that address the anchor bolt shear breakout strength in this kind of construction.
I would appreciate if you could shed some lights into this matter.
ACI 530 Commentary Section 2.1.5.2 states that the shear bond strength of collar joints with mortar could vary from 5 psi to as high as 100 psi. I was trying to find some publications that address the anchor bolt shear breakout strength in this kind of construction.
I would appreciate if you could shed some lights into this matter.






RE: Anchor Shear Capacity in Double Wythe Brick
RE: Anchor Shear Capacity in Double Wythe Brick
RE: Anchor Shear Capacity in Double Wythe Brick
400 plf is pretty small. If the load is not reversible, then place the anchors such that the edge distance in the direction of the load is whatever you need it to be to work.
RE: Anchor Shear Capacity in Double Wythe Brick
RE: Anchor Shear Capacity in Double Wythe Brick
The shear is out of plane pushing away from the building.
I am looking at the mortar joint bonding failure, 5 psi per ACI 530 2.1.5.2.2. What do you think?
RE: Anchor Shear Capacity in Double Wythe Brick
The fall back would be to have your anchor mfr come out and pull test the anchors. I swear I don't work them, but our local Hilti rep has often offered to come out and pull test. You can use Ch 17 of the IBC to determine test requirements.
RE: Anchor Shear Capacity in Double Wythe Brick
RE: Anchor Shear Capacity in Double Wythe Brick
Your most reliable is to test 10% or so of the anchors for 2.5 or 3 x the load in pullout (the way all anchors fail).
RE: Anchor Shear Capacity in Double Wythe Brick
RE: Anchor Shear Capacity in Double Wythe Brick
"You can't really trust the look of mortar becuase some cheap tuck pointers repair only the last 1/2" and do not fix the entire joint."
The whole point of repointing is to replace only the external 1/2" or so. This is effective and hopefully affordable. 'Fixing' the entire joint would mean rebuilding the wall.
RE: Anchor Shear Capacity in Double Wythe Brick
RE: Anchor Shear Capacity in Double Wythe Brick
I think the shear breakout of 1 single bolt should be 5psi (per ACI 530 2.1.5.2.2) x shear cross section = area at bottom and 2 sides of 1 brick
I could not find any other literature that discuss the shear stress of a mortar joint, other than using 5 psi from ACI 530 specified as the shear bond stress between collar joint and brick face.
RE: Anchor Shear Capacity in Double Wythe Brick
Yes, in that situation repointing obviously isn't the answer.
I agree that the condition of the mortar should be checked beyond the external face.
RE: Anchor Shear Capacity in Double Wythe Brick
Dougantholz & Apsix:
My standard spec for working with old buildings addresses this issue by nail point test. I say something along the lines of:
"When the mortar is being re-pointed, if removing 1/3 of the mortar bed does not reveal a sound middle third (sound being defined by capable of sustaining six firm blows of a standard carpenter's hammer driven 3mm headed nail set while yielding to 5mm or less), deep pointing will be required. It is suggested the stability of the wall be maintained by a combination of propping of the overall wall and metal shims in the mortar joints. Stability of the wall remains the responsibility of the contractor at all times, and the contractor is advised to engage an engineer to prepare formworks and falseworks procedures and drawings if they feel professional engineering input would be warranted."
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Anchor Shear Capacity in Double Wythe Brick
RE: Anchor Shear Capacity in Double Wythe Brick